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Brachet C, Laemmle A, Cools M, Sauter KS, De Baere E, Vanlander A, Pandey AV, du Toit T, Voegel CD, Heinrichs C, Verdin H, Flück CE. Insight into the role of TXNRD2 in steroidogenesis through a novel homozygous TXNRD2 splice variant. Eur J Endocrinol 2024; 191:144-155. [PMID: 39097530 DOI: 10.1093/ejendo/lvae090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/21/2024] [Accepted: 06/24/2024] [Indexed: 08/05/2024]
Abstract
OBJECTIVE Adrenal cortisol production occurs through a biosynthetic pathway which depend on NADH and NADPH for energy supply. The mitochondrial respiratory chain and the reactive oxygen species (ROS) detoxification system are therefore important for steroidogenesis. Mitochondrial dysfunction leading to oxidative stress has been implicated in the pathogenesis of several adrenal conditions. Nonetheless, only very few patients with variants in one gene of the ROS detoxification system, Thioredoxin Reductase 2 (TXNRD2), have been described with variable phenotypes. DESIGN Clinical, genetic, structural, and functional characterization of a novel, biallelic TXNRD2 splice variant. METHODS On human biomaterial, we performed whole exome sequencing to identify and RNA analysis to characterize the specific TXNRD2 splice variant. Amino acid conservation analysis and protein structure modeling were performed in silico. Using patient's fibroblast-derived human induced pluripotent stem cells, we generated adrenal-like cells (iALC) to study the impact of wild-type (WT) and mutant TXNRD2 on adrenal steroidogenesis and ROS production. RESULTS The patient had a complex phenotype of primary adrenal insufficiency (PAI), combined with genital, ophthalmological, and neurological features. He carried a homozygous splice variant c.1348-1G > T in TXNRD2 which leads to a shorter protein lacking the C-terminus and thereby affecting homodimerization and flavin adenine dinucleotide binding. Patient-derived iALC showed a loss of cortisol production with overall diminished adrenal steroidogenesis, while ROS production was significantly increased. CONCLUSION Lack of TXNRD2 activity for mitochondrial ROS detoxification affects adrenal steroidogenesis and predominantly cortisol production.
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Affiliation(s)
- Cécile Brachet
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (H.U.B), Hôpital Universitaire des Enfants Reine Fabiola (HUDERF), Paediatric Endocrinology Unit, Avenue J.J. Crocq 15, 1020 Bruxelles, Belgium
| | - Alexander Laemmle
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
- Institute of Clinical Chemistry, University of Bern, 3010 Bern, Switzerland
| | - Martine Cools
- Department of Internal Medicine and Pediatrics, Ghent University; Department of Pediatrics, Division of Pediatric Endocrinology, Ghent University Hospital, 9000 Ghent, Belgium
| | - Kay-Sara Sauter
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University Hospital; Department of Biomolecular Medicine, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Arnaud Vanlander
- Mitochondrial Investigations Laboratory, Ghent University C. Heymanslaan 10, 9000 Ghent, Ghent, Belgium and Department of Internal Medicine and Paediatrics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Amit V Pandey
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
| | - Therina du Toit
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
| | - Clarissa D Voegel
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
| | - Claudine Heinrichs
- Université libre de Bruxelles (ULB), Hôpital Universitaire de Bruxelles (H.U.B), Hôpital Universitaire des Enfants Reine Fabiola (HUDERF), Paediatric Endocrinology Unit, Avenue J.J. Crocq 15, 1020 Bruxelles, Belgium
| | - Hannah Verdin
- Center for Medical Genetics, Ghent University Hospital; Department of Biomolecular Medicine, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Christa E Flück
- Division of Pediatric Endocrinology, Diabetology and Metabolism, Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, 3010 Bern, Switzerland
- Department of Biomedical Research, University of Bern, 3010 Bern, Switzerland
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Maharaj AV. Familial Glucocorticoid Deficiency: the changing landscape of an eponymous syndrome. Front Endocrinol (Lausanne) 2023; 14:1268345. [PMID: 38189052 PMCID: PMC10771341 DOI: 10.3389/fendo.2023.1268345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/28/2023] [Indexed: 01/09/2024] Open
Abstract
Familial Glucocorticoid Deficiency encompasses a broad spectrum of monogenic recessive disorders that theoretically solely abrogate cortisol biosynthesis. In reality, delineating clear genotype-phenotype correlations in this disorder is made complicated by marked phenotypic heterogeneity even within kindreds harbouring identical variants. Phenotypes range from isolated glucocorticoid insufficiency to cortisol deficiency plus a variety of superimposed features including salt-wasting and hypoaldosteronism, primary hypothyroidism, hypogonadism and growth defects. Furthermore, mutation type, domain topology and perceived enzyme activity do not always predict disease severity. Given the high burden of disease and implications of a positive diagnosis, genetic testing is crucial in the management of patients warranting detailed delineation of genomic variants including viable functional studies.
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Affiliation(s)
- Avinaash V. Maharaj
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London (QMUL), London, United Kingdom
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Khatun N, Zaveri S, Salciccioli L, John S. A Rare Case of Coexisting Mutation in Desmin and Thioredoxin Reductase 2 Genes Causing Dilated Cardiomyopathy. Cureus 2023; 15:e40560. [PMID: 37465804 PMCID: PMC10351334 DOI: 10.7759/cureus.40560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2023] [Indexed: 07/20/2023] Open
Abstract
Desmin (DES) maintains the overall structure of cardiomyocytes and cytoskeletal organization within striated muscle cells. Mitochondrial thioredoxin reductase 2 (TXNRD-2) is essential for mitochondrial oxygen radical scavenging. We describe a rare case of dilated cardiomyopathy (DCM) in an 18-year-old female with a heterozygous mutation involving both DES and TXNRD-2 genes.
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Affiliation(s)
- Nazima Khatun
- Internal Medicine, State University of New York Downstate Medical Center, Brooklyn, USA
| | - Sahil Zaveri
- Internal Medicine, State University of New York Downstate Medical Center, Brooklyn, USA
| | - Louis Salciccioli
- Cardiovascular Disease, State University of New York Downstate Medical Center, Brooklyn, USA
| | - Sabu John
- Cardiology, Kings County Hospital Center, Brooklyn, USA
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Kucher AN, Sleptcov AA, Nazarenko MS. Genetic Landscape of Dilated Cardiomyopathy. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422030085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Al-Mubarak AA, van der Meer P, Bomer N. Selenium, Selenoproteins, and Heart Failure: Current Knowledge and Future Perspective. Curr Heart Fail Rep 2021; 18:122-131. [PMID: 33835398 PMCID: PMC8163712 DOI: 10.1007/s11897-021-00511-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/22/2021] [Indexed: 12/18/2022]
Abstract
PURPOSE OF REVIEW (Mal-)nutrition of micronutrients, like selenium, has great impact on the human heart and improper micronutrient intake was observed in 30-50% of patients with heart failure. Low selenium levels have been reported in Europe and Asia and thought to be causal for Keshan disease. Selenium is an essential micronutrient that is needed for enzymatic activity of the 25 so-called selenoproteins, which have a broad range of activities. In this review, we aim to summarize the current evidence about selenium in heart failure and to provide insights about the potential mechanisms that can be modulated by selenoproteins. RECENT FINDINGS Suboptimal selenium levels (<100 μg/L) are prevalent in more than 70% of patients with heart failure and were associated with lower exercise capacity, lower quality of life, and worse prognosis. Small clinical trials assessing selenium supplementation in patients with HF showed improvement of clinical symptoms (NYHA class), left ventricular ejection fraction, and lipid profile, while governmental interventional programs in endemic areas have significantly decreased the incidence of Keshan disease. In addition, several selenoproteins are found impaired in suboptimal selenium conditions, potentially aggravating underlying mechanisms like oxidative stress, inflammation, and thyroid hormone insufficiency. While the current evidence is not sufficient to advocate selenium supplementation in patients with heart failure, there is a clear need for high level evidence to show whether treatment with selenium has a place in the contemporary treatment of patients with HF to improve meaningful clinical endpoints. Graphical summary summarizing the potential beneficial effects of the various selenoproteins, locally in cardiac tissues and systemically in the rest of the body. In short, several selenoproteins contribute in protecting the integrity of the mitochondria. By doing so, they contribute indirectly to reducing the oxidative stress as well as improving the functionality of immune cells, which are in particular vulnerable to oxidative stress. Several other selenoproteins are directly involved in antioxidative pathways, next to excreting anti-inflammatory effects. Similarly, some selenoproteins are located in the endoplasmic reticulum, playing roles in protein folding. With exception of the protection of the mitochondria and the reduction of oxidative stress, other effects are not yet investigated in cardiac tissues. The systemic effects of selenoproteins might not be limited to these mechanisms, but also may include modulation of endothelial function, protection skeletal muscles, in addition to thyroid metabolism. ABBREVIATIONS DIO, iodothyronine deiodinase; GPx, glutathione peroxidase; MsrB2, methionine-R-sulfoxide reductase B2; SELENOK, selenoprotein K; SELENON, selenoprotein N; SELENOP, selenoprotein P; SELENOS, selenoprotein S; SELENOT, selenoprotein T; TXNRD, thioredoxin reductase.
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Affiliation(s)
- Ali A Al-Mubarak
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Peter van der Meer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Nils Bomer
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
- Department of Experimental Cardiology, University Medical Center Groningen, UMCG Post-zone AB43, P.O. Box 30.001, 9700, RB, Groningen, The Netherlands.
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Spracklen TF, Chakafana G, Schwartz PJ, Kotta MC, Shaboodien G, Ntusi NAB, Sliwa K. Genetics of Peripartum Cardiomyopathy: Current Knowledge, Future Directions and Clinical Implications. Genes (Basel) 2021; 12:genes12010103. [PMID: 33467574 PMCID: PMC7830587 DOI: 10.3390/genes12010103] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 02/07/2023] Open
Abstract
Peripartum cardiomyopathy (PPCM) is a condition in which heart failure and systolic dysfunction occur late in pregnancy or within months following delivery. Over the last decade, genetic advances in heritable cardiomyopathy have provided new insights into the role of genetics in PPCM. In this review, we summarise current knowledge of the genetics of PPCM and potential avenues for further research, including the role of molecular chaperone mutations in PPCM. Evidence supporting a genetic basis for PPCM has emanated from observations of familial disease, overlap with familial dilated cardiomyopathy, and sequencing studies of PPCM cohorts. Approximately 20% of PPCM patients screened for cardiomyopathy genes have an identified pathogenic mutation, with TTN truncations most commonly implicated. As a stress-associated condition, PPCM may be modulated by molecular chaperones such as heat shock proteins (Hsps). Recent studies have led to the identification of Hsp mutations in a PPCM model, suggesting that variation in these stress-response genes may contribute to PPCM pathogenesis. Although some Hsp genes have been implicated in dilated cardiomyopathy, their roles in PPCM remain to be determined. Additional areas of future investigation may include the delineation of genotype-phenotype correlations and the screening of newly-identified cardiomyopathy genes for their roles in PPCM. Nevertheless, these findings suggest that the construction of a family history may be advised in the management of PPCM and that genetic testing should be considered. A better understanding of the genetics of PPCM holds the potential to improve treatment, prognosis, and family management.
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Affiliation(s)
- Timothy F. Spracklen
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Graham Chakafana
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Peter J. Schwartz
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, 20135 Milan, Italy;
| | - Maria-Christina Kotta
- Center for Cardiac Arrhythmias of Genetic Origin and Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, 20135 Milan, Italy;
| | - Gasnat Shaboodien
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Ntobeko A. B. Ntusi
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Cape Universities Body Imaging Centre, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
| | - Karen Sliwa
- Hatter Institute for Cardiovascular Research in Africa & CHI, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town 7935, South Africa; (T.F.S.); (G.C.); (P.J.S.); (G.S.); (N.A.B.N.)
- Division of Cardiology, Department of Medicine, Groote Schuur Hospital, Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa
- Correspondence:
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